The French manufacturer team currently have Sainz on loan from Red Bull, who can take back the 23-year-old at the end of the season should their race-winning Australian Ricciardo decide to go elsewhere.

“We need to make plans, we need to be prepared for the worst as always,” Renault Sport F1 managing director Cyril Abiteboul told Reuters at the Azerbaijan Grand Prix.

“So the worst for us would be that we would want to stay with Carlos and that’s not possible. And it can happen, let’s be honest. So we need to plan accordingly.”

Abiteboul said the team were treating Sainz as if he were staying, however.

“We already actually started to work on next year’s car, we had a meeting this week with him to talk about the plan for next year, the objectives and also... the early concept of the 2019 car,” he said.

“It’s a clear sign we are not thinking that, in the back of our mind, he may not be with us. It may happen, but we don’t want to compromise short-term or middle-term performance by starting to mitigate the way we are working with him.”

Sainz, who joined Renault late last season to replace Britain’s under-performing Jolyon Palmer, has been out-qualified by team mate Nico Hulkenberg 3-0 this season and has only three points to the German’s 22.

Abiteboul recognized the youngster was “a bit behind” but said Renault remained fully supportive.

“It would be completely inappropriate to start making judgments only after three races, way too early,” he said. “But it does say something about the quality of his team mate and that’s great, that’s only positive.

“For the rest, we will see. We have a bit of time to specifically think about Carlos. Having said that, we will not delay the thinking process about the alternative in case it cannot work out with him.

“It’s my responsibility to make sure that we have a competitive lineup next year and to present the options to the board of Renault in the coming weeks and months and we will do that.”

RICCIARDO DECISION

Red Bull have yet to decide whether to continue with Renault engines next season or switch to Honda.

Abiteboul said that was unlikely to be the key factor in making up Ricciardo’s mind, however, because power unit performance was converging.

“The four engine manufacturers (Mercedes, Ferrari, Renault and Honda) are very close from one another, particularly in race conditions,” he added.

“There is still a gap in qualifying, we know that, we are working around that on a number of areas. There will be some stuff coming hopefully later this season, I’m pretty sure that Honda are working on the same plan.

“In my opinion, the gap (next year) will not be bigger from the gap we used to have from the previous set of regulations.”

Red Bull must tell Renault what they are doing by the end of May, meaning Ricciardo will know the situation before he has to commit.

The Australian, winner for Red Bull in China two weeks ago and in Azerbaijan last year, has spoken of his interest in joining Mercedes as team mate to four times world champion Lewis Hamilton.

He has also been linked in the media to Ferrari but says he has so far talked only to his current team.

Red Bull won four titles in a row with Renault V8 engines between 2010-13 but have been at loggerheads with the French manufacturer in the V6 turbo hybrid era and there is no ‘wiggle room’.

“Our engine will not be available for very long,” said Abiteboul. “We need to start making orders these days for next year. We have a number of long lead-time items in the engine... and we need to start now.

“We are very clear with Red Bull that it cannot go past what’s written in the regulations. We need to know our quantity (of engines) by the end of May. That’s what they need to work around.”